Deep rock quality assurance coring device and coring method thereof

ABSTRACT

The present disclosure relates to the field of scientific drilling technology and provides a deep rock quality assurance coring device and coring method thereof. The deep rock quality assurance coring device comprises a drilling tool, a drilling bit, a central rod and a core storage body, wherein the drilling bit is mounted at the lower end of the drilling tool, the lower end of the central rod is connected to the core storage body, and the central rod is capable of driving the core storage body to move in the drilling tool in an axial direction of the drilling tool, a reservoir chamber having a lower end opening is arranged in the central rod, a core storage chamber having a lower end opening is arranged in the core storage body.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of International Application No. PCT/CN2018/119535, filed on Dec. 6, 2018, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the field of scientific drilling technology, and in particular to a deep rock quality assurance coring device and coring method thereof.

BACKGROUND

At present, the quality assurance technology of deep rock drilling core is basically in a qualitative and relative quality assurance state, and cannot achieve completely quality assurance of the rock core. In the process of core drilling and core extraction, the rock core will be polluted by formation water or drilling fluid at the bottom of the well, which will affect the in-situ quality, oil and gas content and humidity of the rock core, and the microbial living environment will be changed due to the influence of air after core extraction, which will affect scientific research. At the same time, the loss of oil and gas resources inside the rock core will lead to the distortion of resource evaluation. Therefore, the basic premise of deep rock scientific exploration is to achieve in-situ quality assurance coring.

A large amount of scientific drilling researches have been carried out in China, but the rock coring technology cannot achieve complete quality assurance of the rock core, which is very unfavorable for in-situ environment exploration, oil and gas resources exploration, and deep geological medicine research. It is urgent to provide rock in-situ quality assurance coring technology to lay the foundation for deep rock scientific exploration and research.

SUMMARY

A technical problem to be solved by embodiments of the present disclosure is to provide a deep rock quality assurance coring device and coring method thereof in order to solve a problem that the deep rock coring technology in the prior art cannot achieve completely quality assurance coring and lead to the in-situ quality of the rock core to be affected.

Embodiments of the present disclosure are achieved by providing a deep rock quality assurance coring device, the device comprises a drilling tool, a drilling bit, a central rod and a core storage body for storing a rock core, wherein the drilling bit is mounted at the lower end of the drilling tool, the lower end of the central rod is connected to the core storage body, and the central rod is capable of driving the core storage body to move in the drilling tool in an axial direction of the drilling tool, a reservoir chamber having a lower end opening is arranged in the central rod, a core storage chamber having a lower end opening is arranged in the core storage body, the first valve controlling communication or blocking of the reservoir chamber and the core storage chamber is mounted on the upper end of the core storage body, the second valve closing or opening the lower end opening of the core storage chamber is mounted on the inner wall of the drilling tool;

Before the deep rock quality assurance coring device extracts the rock core, the first liquid is stored in the reservoir chamber, and the lower end opening of the reservoir chamber is closed by closing the first valve, so as to block the reservoir chamber and the core storage chamber, the second liquid is stored in the core storage chamber and the lower end opening of the core storage chamber is closed by a membrane.

Furthermore, the inner wall of the core storage body is provided with a liquid flow path, and when the first valve is opened, the reservoir chamber communicates with the core storage chamber through the liquid flow path.

Furthermore, the liquid flow path comprises a plurality of branching paths and a plurality of openings communicating with each other, and when the first valve is opened, the reservoir chamber, the branching path, the opening and the core storage chamber are sequentially connected.

Furthermore, the plurality of branching paths extend in an axial direction of the core storage body.

Furthermore, the plurality of branching paths are evenly distributed along a circumferential direction of the core storage body.

Furthermore, the plurality of openings are arranged at equal intervals along the axial direction of the core storage body.

Furthermore, the first valve is an electronically controlled valve and the second valve is a flap valve.

Furthermore, the inner wall of the lower end of the drilling tool is provided with a claw for clamping the rock core.

Furthermore, the first liquid is water, and the second liquid is a solution formed by mixing hydroxyl terminated polydimethylsiloxane, crosslinking agent, catalyst and fillers.

The embodiment of the present disclosure further provides a coring method of the above deep rock quality assurance coring device, wherein the coring method comprises the following steps:

Firstly, after the first liquid is stored in the reservoir chamber, the first valve is closed so as to block the reservoir chamber and the core storage chamber, and then the second liquid is stored in the core storage chamber and the lower end opening of the core storage chamber is closed by the membrane to prevent the second liquid from flowing out;

The drilling tool is started, and the drilling tool drives the drilling bit to perform rock breaking work; in the process of rock core extraction, the rock core breaks through the membrane and starts to enter into the core storage chamber, at this time, the second liquid in the core storage chamber starts to be discharged due to the entry of the rock core; in the process of the rock core entering the core storage chamber, the second liquid always wraps the rock core to avoid contamination of the rock core caused by other liquids; and

After the rock core enters the core storage chamber, the coring process is finished, the drilling tool stops working, the second valve is closed, so that the second valve covers the lower end opening of the core storage chamber, and then the first valve is opened to make the reservoir chamber and the core storage chamber communicate with each other, so that the first liquid in the reservoir chamber enters the core storage chamber and contacts with the second liquid around the rock core to trigger in-situ curing and form a sealing film to wrap the rock core, and isolate the rock core from the outside, thereby avoiding changes of the living environment of the microorganisms on the rock core, and at the same time preventing the loss of oil and gas resources inside the rock core from leading to the distortion of the resource evaluation, and finally completely achieving the purpose of quality assurance coring.

In the coring process of the deep rock quality assurance coring device of the present disclosure, when the rock core breaks through the membrane and enters the core storage chamber, the rock core is always wrapped by the second liquid, so as to avoid the contamination of the rock core caused by other liquids in the depth of the formation, and after the rock core enters the core storage chamber, the first liquid in the reservoir chamber enters the core storage chamber and contacts with the second liquid around the rock core to trigger in-situ curing and form a sealing film to wrap the rock core, and isolate the rock core from the outside, thereby avoiding changes of the living environment of the microorganisms on the rock core, and at the same time preventing the loss of oil and gas resources inside the rock core from leading to the distortion of the resource evaluation, and finally achieving the purpose of quality assurance coring and ensuring the in-situ quality state of the rock core, which lays the foundation for deep rock science exploration and research.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings in the following description are some embodiments of the present disclosure. Those skilled in the art can also obtain other drawings based on these drawings without any creative efforts.

FIG. 1 is a schematic structural diagram of the deep rock quality assurance coring device provided in the embodiments of the present disclosure before coring.

FIG. 2 is a schematic diagram of enlarged structure of area A shown in FIG. 1.

FIG. 3 is a schematic diagram of section structure in the B-B direction shown in FIG. 1.

In the drawings, all reference signs are:

1—drilling tool, 2—drilling bit, 3—central rod, 4—core storage body, 5—claw, 6—first valve, 7—second valve, 30—reservoir chamber, 40—core storage chamber , 41—branching path and 42—opening.

DESCRIPTION OF THE EMBODIMENTS

To make the objectives, technical solutions and advantages of the present disclosure clearer, the following further describes the present disclosure in detail with reference to the accompanying drawings and embodiments. It should be understood that the described specific embodiments are merely used to explain the present disclosure rather than to limit the present disclosure.

FIG. 1 to FIG. 3 show a deep rock quality assurance coring device provided in embodiments of the present disclosure. The deep rock quality assurance coring device comprises a drilling tool 1, a drilling bit 2, a central rod 3 and a core storage body 4 for storing a rock core, wherein the drilling bit 2 is mounted at the lower end of the drilling tool 1, the lower end of the central rod 3 is connected to the core storage body 4, and the central rod 3 is capable of driving the core storage body 4 to move in the drilling tool 1 in an axial direction of the drilling tool 1, so as to drive the drilling bit 2 to perform rock breaking work by starting the drilling tool 1, and to drive the core storage body 4 to perform a rock core extracting operation by driving the central rod 3. The inner wall of the lower end of the drilling tool 1 is provided with a claw 5 to clamp the rock core and break the rock core, and a reservoir chamber 30 having a lower end opening is arranged in the central rod 3, a core storage chamber 40 having a lower end opening is arranged in the core storage body 4, the reservoir chamber 30 communicates with the upper end of the core storage chamber 40 through its lower end opening. The first valve 6 is mounted on the upper end of the core storage body 4, and the first valve 6 is an electronically controlled valve. The reservoir chamber 30 and the core storage chamber 40 are controlled to communicate with each other or block each other by opening or closing the first valve 6. The second valve 7 is mounted on the inner wall of the drilling tool 1, and the second valve 7 is an electrically controlled flap valve. The lower end opening of the core storage chamber 40 is closed or opened by opening or closing the second valve 7.

Before the deep rock quality assurance coring device extracts the rock core, a certain amount of the first liquid (not shown in the figure) is stored in the reservoir chamber 30, and the lower end opening of the reservoir chamber 30 is closed by closing the first valve 6, so as to block the reservoir chamber 30 and the core storage chamber 40 to prevent the first liquid from flowing into the core storage chamber 40; the second liquid (not shown in the figure) is stored in the core storage chamber 40 and the lower end opening of the core storage chamber 40 is closed by a membrane (not shown in the figure) to prevent the second liquid from flowing out. After the deep rock quality assurance coring device extracts the rock core, the rock core enters the core storage chamber 40 to discharge a portion of the second liquid, and at the same time, the first valve 6 is opened, so that the first liquid in the reservoir chamber 30 enters the core storage chamber 40 and contacts with the second liquid around the rock core to trigger in-situ curing and form a sealing film to wrap the rock core after the first liquid and the second liquid are contacted with each other, thereby isolating the rock core from the outside.

In the above embodiment, the inner wall of the core storage body 4 is provided with a liquid flow path, and when the first valve 6 is opened, the reservoir chamber 30 communicates with the core storage chamber 40 through the liquid flow path. Specifically, the liquid flow path comprises a plurality of branching paths 41 and a plurality of openings 42 communicating with each other, and when the first valve 6 is opened, the reservoir chamber 30, the branching path 41, the opening 42 and the core storage chamber 40 are sequentially connected; the plurality of branching paths 41 extend in an axial direction of the core storage body 4 and are evenly distributed along a circumferential direction of the core storage body 4, and the plurality of openings 42 are arranged at equal intervals along the axial direction of the core storage body 4, so that the first liquid can flow into the core storage chamber 40 rapidly and uniformly and mix with the second liquid.

In the embodiment, the first liquid may be water, and the second liquid is a solution formed by mixing hydroxyl terminated polydimethylsiloxane, crosslinking agent and catalyst, i.e., the second liquid may be a solution formed by mixing hydroxyl terminated polydimethylsiloxane, methyl trimethylketoxime silane, dibutyl tin dilaurate, graphene and organic montmorillonite, a solution formed by mixing hydroxyl terminated polydimethylsiloxane, methyl trimethoxysilane, dibutyl tin dilaurate, graphene and organic montmorillonite, a solution formed by mixing hydroxyl terminated polydimethylsiloxane, methyl trimethoxysilane , dibutyl tin dilaurate , graphene and boron nitride. In other embodiments, the first liquid and the second liquid may also be other liquids that are capable of forming a sealed protective layer on the rock core after contacting or mixing.

The embodiment of the present disclosure further provides a coring method of the above deep rock quality assurance coring device, wherein the coring method comprises the following steps:

Firstly, after the first liquid is stored in the reservoir chamber 30, the first valve 6 is closed so as to block the reservoir chamber 30 and the core storage chamber 40, and then the second liquid is stored in the core storage chamber 40 and the lower end opening of the core storage chamber 40 is closed by the membrane to prevent the second liquid from flowing out; the second liquid in the embodiment is a solution formed by mixing hydroxyl terminated polydimethylsiloxane, crosslinking agent,catalyst and fillers, which is a viscous liquid, and is capable of closing the lower end opening of the core storage chamber through a sticky film such as a cling film;

After the first liquid and the second liquid are stored, the drilling tool 1 is started, and the drilling tool 1 drives the drilling bit 2 to perform rock breaking work; in the process of rock core extraction, the rock core passes through the claw 5, and breaks through the membrane and starts to enter into the core storage chamber 40 of the core storage body 4, at this time, the second liquid in the core storage chamber 40 starts to be slowly discharged due to the entry of the rock core; in the process of the rock core entering the core storage chamber 40, the second liquid always wraps the rock core to avoid contamination of the rock core caused by other liquids; and

After the rock core enters the core storage chamber 40, the coring process is finished, the drilling tool 1 stops working, and the central rod 3 drives the core storage body 4 to lift upward, at the moment the central rod 3 rises, the claw 5 clamps the rock core, as the rock core is pulled apart, the core storage body moves upward until it crosses the second valve, the second valve 7 is closed, so that the second valve 7 covers the lower end opening of the core storage chamber 40, so as to cover the rock core in the core storage chamber 40, and then the first valve 6 is opened to make the reservoir chamber 30 and the core storage chamber 40 communicate with each other, so that the first liquid in the reservoir chamber 30 enters the core storage chamber 40 through the liquid flow path, and contacts with the second liquid around the rock core to trigger in-situ curing and form a sealing film to wrap the rock core, and the rock core is in a state of quality assurance throughout the whole coring process.

In summary, in the coring process of the deep rock quality assurance coring device of the present disclosure, when the rock core breaks through the membrane and enters the core storage chamber 40, the rock core is always wrapped by the second liquid, so as to avoid the contamination of the rock core caused by other liquids in the depth of the formation, and after the rock core enters the core storage chamber 40, the first liquid in the reservoir chamber 30 enters the core storage chamber 40 and contacts with the second liquid around the rock core to trigger in-situ curing and form a sealing film to wrap the rock core, and isolate the rock core from the outside, thereby avoiding changes of the living environment of the microorganisms on the rock core, and at the same time preventing the loss of oil and gas resources inside the rock core from leading to the distortion of the resource evaluation, and finally completely achieving the purpose of quality assurance coring and ensuring the in-situ quality state of the rock core, which lays the foundation for deep rock science exploration and research.

The above merely describes preferred embodiments of the present disclosure, but is not used to limit the present disclosure. Any modifications, equivalent replacements, improvements and the like within the spirit and principle of the present disclosure shall be all contained in the protection scope of the present disclosure. 

What is claimed is:
 1. A deep rock quality assurance coring device comprising a drilling tool, a drilling bit, a central rod and a core storage body for storing a rock core, wherein the drilling bit is mounted at the lower end of the drilling tool, the lower end of the central rod is connected to the core storage body, and the central rod is capable of driving the core storage body to move in the drilling tool in an axial direction of the drilling tool, a reservoir chamber having a lower end opening is arranged in the central rod, a core storage chamber having a lower end opening is arranged in the core storage body, a first valve controlling communication or blocking of the reservoir chamber and the core storage chamber is mounted on the upper end of the core storage body, a second valve closing or opening the lower end opening of the core storage chamber is mounted on the inner wall of the drilling tool; before the deep rock quality assurance coring device extracts the rock core, a first liquid is stored in the reservoir chamber, and the lower end opening of the reservoir chamber is closed by closing the first valve, so as to block the reservoir chamber and the core storage chamber, a second liquid is stored in the core storage chamber and the lower end opening of the core storage chamber is closed by a membrane.
 2. The deep rock quality assurance coring device of claim 1, wherein the inner wall of the core storage body is provided with a liquid flow path, and when the first valve is opened, the reservoir chamber communicates with the core storage chamber through the liquid flow path.
 3. The deep rock quality assurance coring device of claim 2, wherein the liquid flow path comprises a plurality of branching paths and a plurality of openings communicating with each other, and when the first valve is opened, the reservoir chamber, the branching path, the opening and the core storage chamber are sequentially connected.
 4. The deep rock quality assurance coring device of claim 3, wherein the plurality of branching paths extend in an axial direction of the core storage body.
 5. The deep rock quality assurance coring device of claim 4, wherein the plurality of branching paths are evenly distributed along a circumferential direction of the core storage body.
 6. The deep rock quality assurance coring device of claim 5, wherein the plurality of openings are arranged at equal intervals along the axial direction of the core storage body.
 7. The deep rock quality assurance coring device of claim 1, wherein the first valve is an electronically controlled valve and the second valve is a flap valve.
 8. The deep rock quality assurance coring device of claim 1, wherein the inner wall of the lower end of the drilling tool is provided with a claw for clamping the rock core.
 9. The deep rock quality assurance coring device of claim 1, wherein the first liquid is water, and the second liquid is a solution formed by mixing hydroxyl terminated polydimethylsiloxane, crosslinking agent, catalyst and fillers.
 10. A coring method of the deep rock quality assurance coring device of claim 1, comprising the following steps: firstly, after the first liquid is stored in the reservoir chamber, the first valve is closed so as to block the reservoir chamber and the core storage chamber, and then the second liquid is stored in the core storage chamber and the lower end opening of the core storage chamber is closed by the membrane to prevent the second liquid from flowing out; the drilling tool is started, and the drilling tool drives the drilling bit to perform rock breaking work; in the process of rock core extraction, the rock core breaks through the membrane and starts to enter into the core storage chamber, at this time, the second liquid in the core storage chamber starts to be discharged due to the entry of the rock core; in the process of the rock core entering the core storage chamber, the second liquid always wraps the rock core to avoid contamination of the rock core caused by other liquids; and after the rock core enters the core storage chamber, the coring process is finished, the drilling tool stops working, the second valve is closed, so that the second valve covers the lower end opening of the core storage chamber, and then the first valve is opened to make the reservoir chamber and the core storage chamber communicate with each other, so that the first liquid in the reservoir chamber enters the core storage chamber and contacts with the second liquid around the rock core to trigger in-situ curing and form a sealing film to wrap the rock core, and isolate the rock core from the outside. 